Formula: Al₇[O₃/BO₃/(SiO₄)₃]
Mineral class: silicates
Crystal system: rhombic
Mohs scale: 7
Density (g/cm³): 3.26 - 3.41
Cleavage: distinct - poor
Colors: greenish, blue, violet, brownish
Luster: vitreous - dull
Fluorescence: slight
Pleochroism: strong: black - brown
Largest Dumortierite: 6 cm?
Deposits: Brazil, Canada, France, Madagascar, Myanmar, Namibia, Poland, Sri Lanka, USA
1st Description: 1892

Dumortierite

Origin: Madagascar

Photo by kind permission of © www.cs.cmu.edu/~adg/adg-piimages.html, Alan Guisewite.

Dumortierite Mineral

Origin: Madagascar

Photo by kind permission of © www.mineraltivadar.fw.hu, Tivadar Pécsi.

Dumortierite

Weight: 0.15 ct

Origin: Madagascar

Photo by kind permission of © www.irocks.com, Dr. Robert Lavinsky.

Dumortierite

Weight: 0.21 ct

Origin: Madagascar

Photo by kind permission of © www.irocks.com, Dr. Robert Lavinsky.

Dumortierite

Weight: 0.29 ct

Origin: Madagascar

Photo by kind permission of © www.irocks.com, Dr. Robert Lavinsky.

Dumortierite Mineral

Weight: 0.39 ct

Origin: Ohngaing / near Mogok / Myanmar

Photo by kind permission of © www.crystal-treasure.com, Sieghard Ellenberger.

Dumortierite

Weight: 2.55 ct

Origin: Africa

Foto mit freundlicher Erlaubnis von © www.multicolour.com, David Weinberg.